Passenger transport systems are most commonly used to transport passengers or objects in buildings or structures. For example, a passenger transport system can be designed as an elevator system. Alternatively, a passenger transport system can be designed as an escalator or a moving walkway.
In the following, possible designs of passenger transport systems or embodiments of the invention shall be explained, in most cases using elevator systems. Analogously, embodiments of the invention can also be implemented in passenger transport systems in the form of moving walkways, escalators, and the like.
In general, elevator systems are used to be able to transport passengers, for example, within a structure between different floors. As a rule, an elevator car can be moved for that purpose within a usually vertical elevator shaft. When the elevator car has reached a desired floor, an elevator door and, if applicable, an associated landing door can be opened in order to allow passengers to enter the elevator car or to exit the elevator car.
Functions of the elevator system, such as actuating the drive which moves the elevator car, are usually controlled by a central control unit. The central control unit can particularly also control safety-relevant functions of the elevator system. For that purpose, a safety monitoring unit as part of the control unit or in communication with the control unit can be provided. For example, the central control unit can take into account information that it can receive by processing sensor signals or sensor data. The functions of the elevator system can also be controlled by more than one control unit, for example, by a control unit which, among others, controls the drive, and a further control unit which monitors safety functions. In the following, a central control unit shall refer to any control unit that processes sensor signals and/or generates control signals. The sensor signals or sensor data, for example can originate particularly from door switches or other safety switches which are distributed in the structure receiving the elevator system and, for example, detect or measure locally prevailing conditions or states. In the following, such devices shall be called field devices.
Furthermore, the control unit itself can generate control signals and transmit them to other devices distributed within the structure which, for example, can have actuators implementing the control signals. The actuator can purposefully influence locally prevailing conditions or states. Alternatively, the actuators can, for example, also output information, e.g. optically or acoustically. In the following, devices having actuators shall also be called field devices.
In modern elevator systems, data or signals are transmitted by means of bus systems, sometimes also called “fieldbus systems” or “fieldbuses” for short, between the field devices and the central control unit. As a result, a wiring between the field devices and the central control unit can be simplified and/or data transmission times can be kept short particularly in very large elevator systems, for example, in high buildings.
EP 2 251 293 A1 describes a conventional elevator control device with a fieldbus interface.
U.S. Pat. No. 6,267,219 B1 describes a conventional elevator control device with a fieldbus in the form of a CAN bus.